Slide latch needle selector arrangement



Feb. 11, 1969' R. SCHMlDT SLIDE LATCH NEEDLE SELECTOR ARRANGEMENT Filed March 21, 1967 FIG.- 4

FIG. 3

United States Patent 3,426,550 SLIDE LATCH NEEDLE SELECTOR ARRANGEMENT Richard Schmidt, Stuttgart-Vaihingen, Germany,

assignor to Franz Morat G.m.b.H., Stuttgart- Vaihingen, Germany Filed Mar. 21, 1967, Ser. No. 624,830

Claims priority, application Germany, Jan. 14, 1967,

M 72,411 U.S. Cl. 6613 11 Claims Int. Cl. D04b 15/78, 9/12 ABSTRACT OF THE DISCLOSURE Background of the invention Circular knitting machines are known whose cylinder needles are selectively operated under the control of electromagnetic selectors. When the electromagnetic selector is energized during passage of a needle or its jack, the respective butt is guided onto a rising cam or onto a horizontal cam so that the needles are raised to dilferent heights, as required for certain knitting operations.

Known knitting machines of this type use cylinder needles which have a pivoted latch operated by the yarn of the knitted fabric to move between open and closed positions in accordance with the desired knitting stitches. The electromagnetic selectors have no influence on the turning movement of the latches of the needles.

Slide latch needles are known which consist of a hook element which has a hook and a shaft, and of a latch element which is mounted for sliding movement along the shaft of the hook element for straight movement between a position in which the hook is open, and a position in which the hook is closed. The term slide latch needle will be used in the present application to define only needles of this type, and is not meant to include latch needles of the type having a pivoted latch.

It is known to use slide latch needles in circular knitting machines, and such arrangements have the advantage that the space required for slide latch needles is less than the space required for the conventional construction using needles with pivoted latches. Due to the lesser amount of space required, a greater number of knitting stations, Where yarns are fed to the needles, can be provided around the needle cylinder in the cam box. Furthermore, the operational speed of the knitting machine can be-increased since shorter or less steep rising cam track portions are required so that the Wear of the butts of the slide latch needles is less than the Wear of latch needles having pivoted latches.

However, the constructions according to the prior art using slide latch needles, are incapable of carrying out a needle selection in accordance with a desired knitting pattern at the high speed required in modern knitting machines.

Summary of the invention It is one object of the invention to improve a knitting machine, and particularly a circular knitting machine, by using slide latch needles in the same.

Another object of the invention is to open and close slide latch needles in accordance with a desired knitting pattern by an electromagnetic selector means.

3,426,550 Patented Feb. 11, 1969 ice Another object of the invention is to use cam tracks for guiding the latch elements and the hook elements of slide latch cylinder needles so that the needles are opened and closed and simultaneously raised to different heights, while the latch elements are selectively guided to difierent cam tracks by electromagnetic selector means.

With these objects in view, the present invention relates to a knitting machine which has a movable needle carrier, for example, the needle cylinder of :a circular knitting machine. A set of slide latch needles .is mounted on the carrier, and electromagnetic selector means are operable for causing movement of the latch elements of some selected slide latch needles to a closed position, and for holding the latch elements of other selected slide latch needles in the open position. Preferably, stationary cam means are mounted adjacent the carrier, for example the cam box of a circular knitting machine, and cam means have rising and falling cam tracks engaging the hook elements for moving the same between positions of different heights. The electromagnetic selector means are operable to cause movement of the latch elements to the closed position either before or after a hook element has reachedthe position of greatest displacement. In this manner, difierent stitches are obtained in accordance with a desired knitting pattern, and it will be understood that the electromagnetic selector means are energized in a conventional manner by impulses produced by program control means, such as a program tape read out by contact brushes or photoelectric sensing means.

In the preferred embodiment of the invention, a circular knitting machine has a rotary needle cylinder which supports a set of slide latch needles for axial movement, and a cam box surrounding the needle cylinder and having one rising and falling cam track means for engaging butts of the hook elements for moving the latter between positions of difierent height, and having other cam track means for engaging the butts of the latch elements of the slide latch needles. The last mentioned cam track means includes a first higher rising and falling cam track, and a second lower horizontal cam track bypassing the first cam track and having at least one switching juncture with the same. An electromagnetic selector means is mounted on the cam box at the switching juncture and is operable for moving selected latch elements onto the first cam track, and for holding other selected latch elements on the second lower cam track.

Latch elements shifted to the first higher rising and falling cam tracks move to a position in which the respective needles are closed while being in a high position as required for certain knitting stitches. When the hook elements are raised, and the corresponding latch elements held and 'guided on the lower second cam track, the respective latch needles remain open as required for certain knitting stitches.

Preferably, a third cam track connecting the first and second cam tracks is provided for moving the latch elements to a position closing the already lowered hook elements, as required for other stitches. At the juncture of the second and third cam tracks, another electromagnetic selector is provided for switching selected latch elements between the second and third cam tracks.

Since in the construction of the present invention, the electromagnetic selector means operate latch elements which have a very small mass, the operation is much faster than in known knitting machines in which jacks have to be shifted between different cam tracks for operating associated needles, the jacks having a far greater mass than the latch elements of slide latch needles.

For example, a latch element of 0.2 p. can He moved a distance of 1 mm. by a magnetic force of only 5 p. within a time of only 2.8 milliseconds. This distance is in many cases suflicient to move the elements of a slide latch needle relative to each other to a closed position.

When the slide latch needles are operated at such a speed, three hundred needles can be moved during 1 second to and from knitting positions. This high operational speed cannot be obtained by conventional circular knitting machines for making hosiery, and is only possible for very large knitting machines employing latch needles with pivoted latches. A circular knitting machine constructed in accordance with the invention and using slide latch needles is capable of selecting and operating a slide latch needle within 0.5 millisecond.

In accordance with the invention, the hook element of a slide latch needle is moved to a high position even if no knitted stitch or tuck stitch is to be made, which is accomplished by preventing by the electromagnetic selector means and by a cam track, movement of the corresponding latch element to a closed position.

Consequently, the needle selection according to the desired knitting pattern can be obtained by selection and control of the latch elements only. As explained above, the selection is carried out by electromagnetic selector means, which preferably shift the latch elements between different cam tracks which are designed to move the latch elements to a closing position, or to hold the latch elements in a position in which the respective slide latch needles are opened.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawing FIG. 1 is a fragmentary developed view illustrating a portion of the inner surface of the cam box of a circular knitting machine according to one embodiment of the invention;

FIG. 2 is an axial sectional view of the circular knitting machine taken on line 11-11 in FIG. 1;

FIG. 2a includes six fragmentary axial sectional views taken along portions of FIG. 1 aligned therewith;

FIG. 3 is a fragmentary sectional view taken on line III-III in FIG. 1; and

FIG. 4 is a fragmentary sectional View taken on line IV-IV in FIG. 1.

Description of a preferred embodiment Referring now to the drawing, a circular knitting machine has a needle cylinder 1 with guide grooves 11 extending in axial direction and slidably guiding slide latch needles 2.

In the illustrated construction, each slide latch needle includes a hook element consisting of an open hook 22, a tubular shaft 21, and a butt secured to the end of the tubular shaft 21. The slide latch needle further includes a straight latch element 24 guided in the tubular shaft 21 for straight movement between a position in which hook 22 is closed, and a position in which hook 22 is open. The latch element 24 has a butt 2.5 at the end.

However, instead of the illustrated slide latch needle, another type of slide latch needle may be used. For example, the latch element may be placed adjacent the hook element in the guide groove 11 of the needle cylin der and guided by the guide groove, and not by the shaft of the hook element, to move up and down for closing and opening the hook. In another construction of a slide latch needle, the shaft 21 has a U-shaped cross section with a guide groove in which a fiat latch element is mounted for sliding movement.

The needle cylinder 1 is mounted for rotary movement about an axis of rotation, not shown, and supported on a bearing ring 12 which is secured to the machine frame.

Needle cylinder 1 has an inner gear ring 13 meshing with a drive pinion, not shown, which causes rotation of the needle cylinder with the needles 2. The needle cylinder is surrounded by a ring-shaped cam box 14 on Whose inner surface, cam means are mounted which form cam tracks in the form of channels for guiding the butts 23 of the hook elements, and the butts 25 of the latch elements of the slide latch needles, respectively.

FIG. 1 illustrates the cams in the region of one knitting and feeding station Where a yarn is supplied by a feeding means 201 shown in FIG. 2a. Pairs of cams 103, 104 and 105, 106 form horizontal circumferentially extending cam track portions 3 which are connected by a rising and falling cam track portion 4 formed by a pair of cams 101 and 102. Cam track 3, 4- guides the butts 23 of the hook element, as schematically shown in FIG. 1, and the respective hook elements assume the positions shown in FIG. 2a turned an angle of In the lower portion of the cam box, other cam track means are formed for the butts 25 of the latch elements 24 by cams secured to the inner surface of the cam box 14. Pairs of cams 111, 112 and 113, 114 form horizontal circumferential cam track portions 5 which are connected by a rising and falling higher first cam track portion 7, and by a lower horizontal circumferential second cam track portion 5a. The higher cam track 7 includes a rising portion 7a, a horizontal portion 7b, and a falling portion 70. A third cam track 10 connects the lower cam track 5a with the falling cam track portion '70.

During rotation of the needle cylinder 1, butts 25 moving along cam track 5 in the direction of the arrow P, are guided at the switching juncture 6 either into the rising cam track portion 7a or move along the horizontal cam track portion 5a. At the second juncture 9, butts 25 can also be shifted to move along cam track 10, or be held for further movement along cam track 5a.

The shape of rising and falling cam track 7 corresponds to the shape of cam track 4 so that a slide latch needle closed at the juncture 6 will remain closed while rising to a higher position, if butt 25 of its latch element 24 moves along cam track 7 while butt 23 of the correspond ing hook element 22 moves along cam track 4.

However, in the example illustrated in the drawing, all butts 25 of latch element 24 are guided along the lower cam track 5a, while the hook elements 22 are raised by cam track 4 so that the hooks are open while the hook elements are in the highest position, as shown in FIG. 2a.

Butt 25 of one latch element has been moved up along cam track 10, and is moving down the falling cam track portion 70, as also shown in the section of FIG. 2. Since the respective latch element is raised, while the respective hook element has already descended, the slide latch needle is closed, as shown in FIG. 2a. The first and the last needles 2 are also closed since butts 23 are at the height of cam track portion 3, and butts 25 are at the height of cam track portion 5.

In accordance with the invention, butts 25 of latch elements 24 are selectively shifted or switched at juncture 6 either to cam track 7, or to cam track 5a, and the butts moving along cam track 50 are shifted at the juncture 9 either to cam track 10, or held for continued movement on cam track portion 5a.

If a butt 25 is shifted to cam track portion 7, the respective needle will rise and descend in closed position. If a butt is held on cam track portion 5a, only the hook element 22 will rise and descend as shown in FIG. 211 so that the needle is open. If a butt is moved all the way along cam track portion 5a to cam track 5, the respective needle will close when butt 23 of the respective hook element arrives at cam track 3. If a butt 25 is shifted to cam track 10, the hook element will be closed by the latch element during descent as shown for the second needle from the right in FIG. 2a.

In the event that butts 25 are guided along the lower track 511, as shown in FIGS. 1 and 2a, the raised needle hooks catch the yarn supplied by the feeding means 201, but since the hooks are not closed, the loop cannot be cast oft so that tuck stitches are made. If the butt 25 of a latch element 24 is guided along cam track 7, the needle remains closed, and no yarn is caught. Consequently, no loop is formed at this knitting station.

If butt 25 is guided onto cam track 5a, and the respective needle is closed during descent, as shown in FIG. 2a, the old loop is cast off and a new loop is formed.

In accordance with the invention, electromagnetic selector means are provided for carrying out the selection of the three possible operations. The first electromagnetic selector is provided at the juncture 6 and includes a pair of solenoids 301, 302, and pole shoes 307 and 309. Pole shoe 307 of solenoid 301 has a slanted face 308 forming a portion of the surface of cam track 711 which is mainly formed between cams 107 and 108. Pole shoe 309 of solenoid 302 has a face 310 forming a portion of the lower surface of cam track 5a in the region of juncture 6 as also shown in FIG. 3.

A second electromagnetic selector has two solenoids 303 and 304 with pole shoes 312 and 311. Pole shoe 312 has a slanted face forming a portion of the upper surface of cam track which is otherwise formed between cam 108 and cam 109. Pole shoe 311 has an end face which forms a portion of the lower surface of cam track 5a in the region of juncture 9. Cam track 5a is otherwise formed between cams 108, 109, and cam 110, While the horizontal cam track portions 5 are formed between pairs of cams 111, 112 and 113, 114.

The solenoid 301, 302, 303, 304 of the electromagnetic selector means are energized in accordance with a program by program control means which may include a program tape having perforations or light permeable markings sensed by suitable sensing means to produce command impulses which are given to the solenoids. Separate tracks are provided on the program tape for each solenoid, and the arrangement is such that only one of the pair of solenoids 301, 302, and one of the pair of solenoids 303, 304 can be simultaneously energized.

When solenoid 301 is energized by a command impulse, a butt 25 arriving at the switching juncture 6 is attracted to face 308 of pole shoe 307 and is moved by the needle cylinder onto cam track portion 7a. However, when solenoid 302 is energized by a program impulse, the respective butt 25 is attracted to end face 310 and will be moved by the needle cylinder along the lower cam track portion 500a.

If at the switching juncture 9, solenoid 304 is energized by a program impulse, pole shoe 311 attracts butt 25 and the needle cylinder moves the butt further along cam track portion 5a. However, if solenoid 303 is energized by a program impulse, a respective butt at the juncture 9 is attracted by the end face 313 of pole shoe 312 and the needle cylinder moves the butt along the rising cam track portion 10 to the falling cam track portion 70 and along the same to cam track 5 and to the next knitting and feeding station where corresponding cam track means 3, 4 for the hook elements, and 5a, 7, 10 for the latch elements are provided so that another selection can be carried out in accordance with the program to produce the desired knitting pattern.

The horizontal width of pole shoes 307, 309, 311, and 312 is not greater than the pitch distance between two adjacent slide latch needles so that each needle can be independently selected.

In accordance with the invention, cam track 4 has substantially the same shape as cam track 7 and is constructed so that the hook elements are raised to the highest position even if no stitch, or a tuck stitch is to be made. Consequently, the selection of needles for knitting a specific pattern, is effected by the selection and control of the latch elements only. If the hook elements are closed during rising and falling due to guidance of the butts of the latch elements on cam track 7, the needles are not opened at all, as explained above, no yarn is caught by the same, and the old loop is not cast off.

This arrangement is particularly advantageous for kniting a pattern having differently colored yarns. At each knitting station, the feeding means 201 supplies a yarn of a dilferent color so that at one knitting station only those needles catch the yarn whose color is to appear on the right side of the knitted fabric. Needles which are to knit a yarn of a different color, are closed by guiding the butts of the respective latch elements onto cam track 7.

Those needles which knit and receiveat the respective knitting station a yarn supplied by the feeding means 201 to the hook, are closed in the region where the loops are formed by guiding the respective butt onto cam track 10, whereupon the old loop is cast off when the closed needle is lowered to the level of cam track 5.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of selector arrangements for the needles of knitting machines differing from the types described above.

While the invention has been illustrated and described as embodied in a slide latch needle selector arrangement including cam tracks and electromagnetic selector means for operating the latch element of the needles, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any Way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a knitting machine, in combination, a movable needle carrier; a set of slide latch needles mounted on said needle carrier, each slide latch needle comprising a hook element and a latch element slidably mounted in said hook element for placing said latch needle in an open position and in a closed position; and. stationary electromagnetic selector means passed by said carrier and by said latch needles and being operable for causing movement of said latch elements of some selected latch needles to said closed position, and for holding said latch elements of other selected latch needles in said open position.

2. A knitting machine as claimed in claim 1 and comprising stationary cam means adjacent said carrier and having rising and falling cam track means engaging said hook elements for moving the same during movement of said carrier between positions of different displacement; and wherein said electromagnetic selector means are operable to cause movement of said latch elements to said closed position selectively before and after a hook element has reached the position of greatest displacement.

3. A knitting machine as claimed in claim 2 wherein said carrier is a rotary needle cylinder; and comprising a cam box surrounding said needle cylinder and having said cam means, said electromagnetic selector means being mounted on said cam box.

4. In a circular knitting machine, in combination, a rotary needle cylinder; a set of slide latch needles mounted on said needle cylinder for axial movement and for rotation with the same, each slide latch needle comprising a hook element, and a latch element slidably mounted on said hook element for placing said latch needle in an open position and in a closed position; cam box means surrounding said needle cylinder and having one rising and falling cam track means for engaging said hook elements for moving the same in axial direction of said needle cylinder between positions of different height, and having other cam track means for engaging said latch elements including a first higher cam track, and a second lower cam track bypassing said first higher cam track and having at least one switching juncture with the same; and electromagnetic selector means located at said switching juncture and being operable for causing movement of said latch elements of selected slide latch needles onto said first higher cam track so that the respective slide latch needle is placed in said closed position, and for holding said latch elements of other selected slide latch needles on said second lower cam track so that movement of said hook elements to a high position places the respective slide latch needle in said open position.

5. A knitting machine as claimed in claim 4 wherein said other cam track means include a third rising cam track connecting said second lower cam track with said first higher cam track at a second switching juncture; and wherein said electromagnetic selector means include a first electromagnetic selector located at said first mentioned juncture, and a second electromagnetic selector located at said second juncture, each of said electromagnetic selectors being operable for causing movement of said latch elements of selected needles onto said first higher cam track for placing the respective latch needles in said closed position, and for holding said latch elements of other selected needles on said second lower cam track for maintaining the respective needles in said open position, said one rising and falling cam track means having the highest portion thereof located axially aligned with the portions of said first and second cam tracks located between said switching junctures.

6. A knitting machine as claimed in claim 5 wherein said first electromagnetic selector includes a first electromagnet energizable for guiding selected latch elements from said second lower cam track onto said first higher cam track, and a second electromagnet energizable for guiding other selected latch elements onto said second lower cam track; and wherein said second electromagnetic selector includes a third electromagnet energizable for guiding selected latch elements onto said third rising cam track, and a fourth electromagnet energizable for holding selected latch elements on said second lower cam track to continue movement thereon.

7. A knitting machine as claimed in claim 6 wherein said first electromagnet includes a pole shoe having a face forming a portion of the upper surface of said first higher cam track at said first switching juncture, wherein said second electromagnet includes a pole shoe having a face forming a portion of the lower surface of said second cam track at said first juncture; wherein said third electromagnet includes a pole shoe having a face forming a portion of the upper surface of said third cam track at said second switching juncture, and wherein said fourth electromagnet includes a pole shoe having a face forming a portion of the lower surface of said cam track in the region of said second switching juncture.

8. A knitting machine as claimed in claim 7 wherein said rising and falling cam track means which engages said hook element has substantially the same configuration as said first higher cam track of said other cam track means which engages said latch element so that needles whose latch elements are guided along said first cam track remain closed while rising and descending.

9. A knitting machine as claimed in claim 8 wherein said second cam track is horizontal; and wherein said third cam track is a rising cam track connecting said second switching juncture with a falling portion of said first cam track.

10. A knitting machine as claimed in claim 5 wherein said hook element of each needle has a first butt, and said latch element of each needle has a second butt; and wherein said first butts are guided along said one rising and falling cam track means, and said second butts are guided along said other cam track means during rotation of said needle cylinder, said one cam track means being located at a higher level than said other cam track means; and wherein said cam box means has horizontal cam track portions at said higher level leading to and from said one cam track means, and horizontal cam tracks at said lower level leading to and from said second cam track of said other cam track means and being located at the same level as the same, said second cam track be' ing horizontal.

11. A knitting machine as claimed in claim 4 wherein said electromagnetic selector means includes a first electromagnet energizable for guiding selected latch elements from said second lower cam track to said first higher cam track, and a second electromagnet energizable for guiding other selected latch elements onto said second lower cam track.

References Cited 

